Photographic-printing machine



Nov'. 13 1923: E. SANKEY rno'roemwmc PRINTING MACHINE F11e Jan- 18. 1923 2 Sheets-Sheet 1 Nov. 13, 1923; r E. SANKEY PHOTOGRAPHIC PRINTING MACHINE Filed Jan. 18. 1925 2 Sheets-Sheet 2 [far/435: E 54'4/47 W Patented Nov. 13, 1923.

UNITED STATES EDWARD SANKEY, OF BARROW-IN-FURNESS, ENGLAND.

PHOTOGRAPHIC-PRINTING MACHINE.

Application filed January is 1923. Serial No. 613,513.

To all whom it may concern Be it known that I, EDWARD SANKEY, a subject of the King of Great Britain and Ireland, and resident of 88 Duke Street, Barrow-in-Furness, England, have invented certain new and useful Improvements in Photographic-Printing Machines, of which the following is a specification.

This invention relates to photographic printing machines and more particularly to what are known as bromide printing boxes, its object being to provide simple and efiicient means for printing individual positives in a rapid and economical manner.

Usually a light box is employed on which the negative is carried. The operator places the bromide paper or card over the negative, there being suitable setting gauges for the purpose of ensuring correct positioning, and a movable platen is then brought down upon the bromide paper to hold it in firm contact with the negative whilst the light is switched on for the requisite period.

My invention comprises the improved platen operating and light controlling mechanism hereinafter described and claimed.

Referring to the accompanying sheet of explanatory drawings Figure l isa side elevation and Figure 2 an end elevation of a photographic printing machine constructed according to this invention.

The same reference letters in the two views indicate thesame parts.

In accordance with my invention, the platen a is operated mechanically and carried by a stem 5 supported by a collar 2' which rests normally on one of the collars i on trunnion pieces pivotally carried by two radius links or arms 0 and (Z which are themselves pivotally attached to the frame of the machine at e and 7 respectively. The platen is pressed towards the negative, mounted on the sloping top of the light box 9, by a compression coil spring h coiled around the platen stem. The collar 2' limits the outward movement of the platen under the spring action.

The lower arm (Z has a lug-like projection (Z thereon on its underside, which is adapted to engage or rest upon a corresponding projection upon a rocking or swinging member 9 fulcrumed about the pivot f of the said lower arm, and having a roller 70 thereon engaged by a cam groove Z which may be formed in a plate attached to the inner side of the Worm wheel m. gaging cam and roller serve to actuatethe platen a, but the necessary pressure between the bromide paper and the negative is applied through the medium of the lever 71 which, with an adjustable spring .0, is pivoted upon the lower arm (Z. One endof the said lever 71, is, as shown at Figure 1, engaged or in abutment with the upper extremity of the aforesaid rocking member y so that when the said member moves in the direction to lower the platen, pressure is applied to the arm (Z and hence to the platen a. The inter-engaging or abutting faces of the said lever 17, and rocking member j are shaped as shown, so that if the platen meets an obstruction, the resistance of the lower arm to movement under the action of the rocking member causes the end of the lever to rise clear of the operative end of the said member. The latter can then continue to oscillate without the platen being brought into contact with the negative. I This arrangement acts as a safety device to prevent the hand of the operator being trapped and damaged or an article being forced so firmly against the negative as to break the same.

In addition to the cam groove Zbefore referred to, whereby the platen is operated, I provide two similar cam plates 79 (the plate p being fixed to the wheel m while the plate 29 is adjustably secured to the wheel m by bolts projecting through elongated slots 79 (see Fig. 1) in the cam plate 10 The said cam plates rotate in unison with the wheel m carrying the cam groove Z and serve to actuate the lever g, by which the switch for the electric lamp in the light box The said inter-en g is opened and closed. By adjusting the i said cam p the period during which the light is switched on in the light box can be varied to suit the character or quality of the negative from which prints are being made. A master switch (not shown) is provided for the operator to prevent the light being switched on. r

The worm wheel m, in the example illustrated, is adapted to be actuated through worm 1" and other gearing by an electric motor or other source of power at a speed which is governed by the rate at which the operator can feed the bromide sheets or cards to the machine.

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